Patent GB-1209247-A (GB)
Title: Improvements in and relating to photographic exposure counters
IPC: G03B1/66
Filed: 1968-10-29
Abstract: 1,209,247. Roll-film cameras. RICOH K. K. Oct.29, 1968 [Nov. 7, 1967], No. 51207/68. Heading G2A. A film counter for a roll-film camera is adapted to count exposed frames of either of two different predetermined lengths of film, e.g. lengths corresponding to 12 or 24 exposures. A lever 40 Fig. 2 is axially displaced upon its shaft 39 against the bias of a spring 41 by a tongue element 40b engaging a cam 43 rigid with a rotatable knob 3. The knob is manually set to one of two positions so that the lever is set to permit the counter to operate for 12 frames as shown in solid line or 24 frames as shown in dotted line. A numeral indicating disc is rigidly attached to a ratchet wheel 35 rotatably mounted upon a shaft (33) Fig. 7 (not shown), and urged in a clockwise direction by a spiral spring (38). A pawl 31 engages the teeth of the ratchet wheel and is spring mounted on one end of a lever 29, the other end of which carries a roller urged against a cardioid arm 22 which is rotated via intermediate gears 16, 17, 18 by a film metering roller 19. A film wind knob 2, through intermediate gears 11, 10 and 12, rotates a shaft 8 to which a film take-up spool is coupled via a spiral spring (13) Fig. 8 (not shown), a ratchet wheel 12 being rigidly fixed to the drive for the spool. The relative motion permitted between gear 7 and ratchet wheel 12 enables the gear 7 to communicate with a shutter loading mechanism after a film frame has been wound on. A three arm lever 32 mounted about a pivot 28b has an arm (32b) Fig. 11 (not shown), for engaging ratchet wheel 12, on arm (32c) for engaging a profiled portion 36a of disc 36 and an arm (32a) for engaging notches (23a), (23b) Fig. 10 (not shown), provided is discs 23, 24 which rotate with gear 18, one disc (23) being rigid with gear 18 and the other spring coupled to disc (23) and allowed a limited amount of angular rotation therewith. In operation of the counter, a film is loaded into the camera and the camera back 1a shut to urge lever 27 to the position shown so that gear 17 meshes with gear 18. The three arm lever is prevented by portion 36a of disc 36 from engaging ratchet wheel 12 and notched discs (23), (24). Rotation of film wind knob 2 rotates ratchet wheel 35 and disc 36 via spiral spring (38) until lever 32 no longer engages portion 36a; further winding of the film is prevented by lever 32 engaging slots (23a, 24a) and thus ratchet wheel 12. Operation of shutter release button (not shown) also rotates lever 32 through a small angle in the clockwise direction to disengage the lever from the notched discs, the spring coupling between immediately causing the notches to be no longer aligned and preventing a return movement of lever 32. Ratchet wheel 12 is also now free to rotate and operation of film wind knob 2 is possible. One complete rotation of gear 18 causes cardioid arm 22 to reciprocate pawl 31 and thus move ratchet wheel 35 one tooth, during this movement the three arm lever 32 frictionally engages the periphery of spring mounted disc (24) to align the notches and allow the lever 32 to engage the notches. After the twelfth exposure a pin 37 attached to ratchet wheel 35 moves lever 40 which then engages pawl 31 and a pin (32a) Fig.4 (not shown), on arm (32c) of lever 32. The trailing end of the film can thus be wound on. For operation with films having 24 exposures, knob 3 is adjusted so that lever 40 is not engaged by pin 37, and counting continues until portion 36a engages the three arm lever 32 and render it inoperative, at this instant pawl 31 engages a portion of ratchet wheel 35 having no teeth, and the trailing end of the film can again be wound on. To return the mechanism to its initial position after exposure of a 12 exposure film, opening of the camera back allows lever 27 to move to the left, demeshing gears 17, 18 and moving lever 32 to an inoperative position, numeral disc 36 and ratchet wheel 35 are then returned to the initial position by the action of spring (38).